Delaying the Soprano Spot Mic

[David Spearritt]

Over the years, I have been recording many sopranos (and other singers), both professional and accomplished students in high quality acoustics. They are most often accompanied by piano, but sometimes a chamber ensemble.

My most common setup is a high quality omni pair (700-900mm spacing) as the mains with a spot mic on the soprano to give focus, but to also balance, as I often set the mains to be ideally placed for the accompaniment and not the singer. The singer spot mic distance is of the order of 1.5m with her distance to the main pair more than that. In general, I am very happy with the results, the sound and balance is glorious.

However, sometimes, depending on singer voice type, I notice a slight "flanging" or fuzzy "phasey" image in the vocal sound, that is not solved convincingly by changing the spot mic level or repositioning mics. To my ears, an improvement to the "coherence" or solidity of the vocal sound can to be obtained by slightly delaying the spot to after the main pair, but its still not "perfect". (Quotes used here to subdue the literalists. )

Has anyone else noticed this sort of effect, when recording classical sopranos in a concert hall acoustic and what techniques were useful to re-focus the vocal.

I have read some ideas from:
http://www.gearslutz.com/board/remot...al-recording.h

[fallforward]

I now there are time align processor that you can buy, and also equations one can do on there own to align the mics. But yes if you have a powerful singer that you are close micing, along with the spaced pair, some sort of compensation is usually in order. I just do it by ear nudging the audio file.

Good Luck man!
Robby

[Larry Elliott]

David
I too do a lot of similar recordings. I have tried the idea of delay on the soloist, but generally this makes it worse rather than better. I tend to think that this is related to the soloist being closer to one of the mains than the other, and hence sounding hard left or right without the spot.

Currently I am editing Creation and am finding the best compromise to be to provide enough of the spot to get the “position” correct only.

Best
Larry

[David Spearritt]

Robby, do you find that your best nudging makes the spot delayed past the mains ?

Larry, I get the issue you mention when doing live concerts, and there's not much that can be done. But I am referring to "studio" gigs, where I have control and can position the singer in the middle of the main pair.

[Jan_M]

My typical setup for this type of gig is a 5 mic setup, mains, usually an AB, stereo spot for piano and a spot for the singer. I have found in my experience that delaying the spots does indeed help and allows me to mix the spots in a lot less than without delaying. I usually place the main pair for a good balance and use the spots for a bit of focus.

As far as the phasey sound, I usually do one of two things which help, first I adjust mic position, I find that height usually plays the biggest difference otherwise I use a piano blanket or equivalent strategically placed in front of the singer on the floor to cut some reflections. One of these usually does the trick if not I switch to a different setup or spacing between the mics. I know you mentioned mic positioning doesn't help but I find it can help to at least minimize the effect.

[fallforward]

Yeah. Pushing the spot mic back much the same way you would push the front mains back in a satelite FOH system. It is never much of a move just a few milliseconds, and not as a rule. I usually only have to do this when the logisitics of the hall force me to have the main pair further back than I would like.

[Recording David]

I did some sessions with Simon Eadon at the end of last year and learned a pretty cool tip for soprano (or other singer) and piano.

Simon was using a pair of MK2S pointing in at the 'tail' end of the piano (as discussed in the epic classical piano recording thread). He would set up a pair of TLM 170 (card) about 2 ft out from the curve of the piano (about 10" apart and hard panned). Put the singer about 3 ft from the mics with mics (obviously) at head height.

Delay problems or spots are therefore removed from the equation. Simple, and sounds fantastic.

[studer58]

Originally Posted by David Spearritt

Over the years, I have been recording many sopranos (and other singers), both professional and accomplished students in high quality acoustics. They are most often accompanied by piano, but sometimes a chamber ensemble.

My most common setup is a high quality omni pair (700-900mm spacing) as the mains with a spot mic on the soprano to give focus, but to also balance, as I often set the mains to be ideally placed for the accompaniment and not the singer. The singer spot mic distance is of the order of 1.5m with her distance to the main pair more than that. In general, I am very happy with the results, the sound and balance is glorious.

However, sometimes, depending on singer voice type, I notice a slight "flanging" or fuzzy "phasey" image in the vocal sound, that is not solved convincingly by changing the spot mic level or repositioning mics. To my ears, an improvement to the "coherence" or solidity of the vocal sound can to be obtained by slightly delaying the spot to after the main pair, but its still not "perfect". (Quotes used here to subdue the literalists. )

Has anyone else noticed this sort of effect, when recording classical sopranos in a concert hall acoustic and what techniques were useful to re-focus the vocal.

I have read some ideas from:
http://www.gearslutz.com/board/remot...al-recording.h

Hi David
I'm assuming you're panning the spot to the same location in the left/right spread stereo spectrum that the voice occupies in the main pair alone...so that there is no discrepancy or 'smearing' of the image spatially ? What pattern spot mic are you using..perhaps cardioid or hyper card ? This is accepted wisdom,but can sometimes add too much 'clarity' or isolation and it's possible to break rules a little by using an omni spot much closer than you'd typically use the previously named types. You still get the spotting function, but with a bit more of the room ambience into the bargain, so the spot sounds more integrated and less pasted on. In addition, be careful of the floor to mic height in relation to the soprano to mic distance, since what you describe could be little more than garden variety comb filtering due to floor reflections destructively interfering (ie partially cancelling) the direct vocal spot path length...esp if the spot mic is on a low stand ? Have you tried a little artificial reverb on the spot, to sink it into the sonic fabric of the room sound, and experiment with some early reflections added to give it a bit of 'precedence effect' (but not too much) Delaying it by a few ms can be good too, depending of the relative distances of main pair:soprano and spot:soprano. I'm in Australia too, so we might have been listening to some of the same source influences for our guidance (eg ABC Classic FM) ? Hope this helps,
Ray

[David Spearritt]

Originally Posted by Recording David

I did some sessions with Simon Eadon at the end of last year and learned a pretty cool tip for soprano (or other singer) and piano.

Simon was using a pair of MK2S pointing in at the 'tail' end of the piano (as discussed in the epic classical piano recording thread). He would set up a pair of TLM 170 (card) about 2 ft out from the curve of the piano (about 10" apart and hard panned). Put the singer about 3 ft from the mics with mics (obviously) at head height.

Delay problems or spots are therefore removed from the equation. Simple, and sounds fantastic.

David, interesting setup, but I don't quite understand the arrangement for the singer. Was she facing the piano, and the 170's had their backs to the piano?

[David Spearritt]

Hi Ray, many thanks for the tips. The soprano is centre in both the main pair and the spot is panned centre. I have tried reverb on the spot but the problem sounds like one of time alignment, rather than image smearing or reverb ratio problems. Unfortunately it will be difficult to get clearance otherwise I would post a sample.

My main trouble with requiring delay on the vox spot is that I have to multi-track, rather than use a minimal analog mixer and stereo recording, which is my preference.

[Ozpeter]

I guess it's not answering the actual question, but where there's a singer and a piano in a good acoustic, and it's not a performance in front of an audience, there has to be (imho!) a means of arranging them in front of a stereo pair such that a satisfactory result is obtained.

Personally if I did feel the need to employ a spot mic when recording piano and voice, I would favour the voice with the main pair (which would be MS) and restore the balance with the spot on the piano - also using that to pan the piano image to where I wanted it to be. Doing it the other way round just feels all wrong to me. Which isn't to say that others have not produced very fine results using that technique!

I've never felt the need to add delay.

(I'm ignoring the chamber ensemble scenario as that's more of a 'it depends' thing, I'd say).

[Recording David]

Originally Posted by David Spearritt

David, interesting setup, but I don't quite understand the arrangement for the singer. Was she facing the piano, and the 170's had their backs to the piano?

Yes, it's as you describe.

[BLP]

Yeah, I've done the delay thing a bit. I, too, have found that it's not an every time thing, but it has happened. I always try to optimize placement of the musicians and the mics, but sometimes that just not enough. I'll try the time alignment and go from there.

Regarding the spot being slightly after the main pair, I know what you're saying. I've found that, if things can't be perfectly aligned (i.e. singer moves, mics move, etc.), placing the spots a little after the mains is way less offensive than a little before.

[fifthcircle]

Any time you spot a soloist in a concerto setting (or other similar solo/ensemble/instrument), you run the risk of having the exact issues you describe. A short delay to time align can fix it, but doesn't always. The more coincident the center pair is, the better the delay will work. The sound you hear is like comb filtering- caused because a couple milliseconds of lag between your spot and your mains.

I think your problem is this. While your main pair isn't spaced terribly wide, it is wide enough that the delay from the spot to each mic is not exactly the same. Therefore, when you delay it, there is still a bit of a mismatch in your time alignment. When dealing with these small distances, I find it is very important to get your delay times as accurate as possible. You can fudge on distant spots because the purpose is more about your front to back image than an exact alignment.

That being said, the only other suggestion to fix the issue would probably lie with reverb sends after aligning. I would probably put a touch more on spot to help mask the comb filtering issue. Once it is there, if you can't fix it with alignment, you're likely not going to get rid of it completely- you can only mask it.

Good luck.

--Ben

[BLP]

Originally Posted by fifthcircle

I think your problem is this. While your main pair isn't spaced terribly wide, it is wide enough that the delay from the spot to each mic is not exactly the same. Therefore, when you delay it, there is still a bit of a mismatch in your time alignment...

Brilliant! I can't believe I never put that all together. Thank you for clearing up one more mystery of the world for me!!! Now, if you could only solve my "getting somebody else to buy me millions of dollars worth of gear" problem...

Seriously though, that makes perfect sense. I've always had much better luck with the delay thing when using a coincident (or more likely a near-coincident) main pair.

[fallforward]

This is also one reason why I favor XY over the spaced pair. (And also becuase I only have one high end omni!)

Good Luck man!
Robby

[MichaelPatrick]

Yea, this problem sucks.

Normally I delay spot mics too. I use only highpass filters, but when this problem comes up I'll try a touch of surgical EQ to overcome the negative combing (cut, boost, or both), and mixed with some gentle ambiance processing it often helps. There are times, though, when nothing works very well.

It's doubly hard when a soprano sends tremendous energy everywhere -- as when they move their head left and right sending their image flying like a ping pong ball back and forth across the stage.

[tenor39]

Are you multi-tracking or mixing to stereo live? If you're multi-tracking, you can time align in mixdown in your DAW. I always do an impulse recording (usually two sticks or my hands slapped together) with all mic's open to get a time marker that I can use to align everything to the main stereo pair. Works wonders and takes very little time to align in the computer. If you're mixing it live, a delay unit might work OK, but you'll have to get good distance measurements to make the correct calculations.

[Plush]

I'm just putting the person singing always placed on the LFT. side. That way they are in "concert' position and also being picked up more by the left main mic. It also gets them fully away from the central piano sound. Then adding in a card. spot and panning as far LFT. as the main pair tells me to. I used to time align everything but I no longer do it. It sounded too discrete to me. I like it blended in the room as the ear would hear it.

I suggest that putting your singer in the middle is part of the problem.

However, you are an expert and I think that placement in the recording room is always the first thing to change.

[David Spearritt]

Originally Posted by Ozpeter

I guess it's not answering the actual question, but where there's a singer and a piano in a good acoustic, and it's not a performance in front of an audience, there has to be (imho!) a means of arranging them in front of a stereo pair such that a satisfactory result is obtained.

Personally if I did feel the need to employ a spot mic when recording piano and voice, I would favour the voice with the main pair (which would be MS) and restore the balance with the spot on the piano - also using that to pan the piano image to where I wanted it to be. Doing it the other way round just feels all wrong to me. Which isn't to say that others have not produced very fine results using that technique!

I've never felt the need to add delay.

(I'm ignoring the chamber ensemble scenario as that's more of a 'it depends' thing, I'd say).

Peter, these are all good points and should work well. But I find that to get the balance with a single pair favouring the singer, the piano has to be on half stick. I also don't like the spot on the piano narrowing its image too much.

I like recording in a "studio" setting with the piano on full stick, and so have to move the soprano further forward than she would be in a lieder recital position for good balance. I then mic the piano with the main pair for full stick richness as if it was a solo piano recording and find that a spot on the singer is preferred. I would rather have a narrower image on the singer than the piano.

I will see if I can post a sample to explain better.

[boojum]

I had a problem recording the Messiah with an AB array above the conductor and the soloists on an MS in front of them. There was an obvious difference between what the AB omnis and the up close and personal MS were hearing. I had to gradually delay the soloists mic until it matched the AB's. Then I had to at a small touch of reverb to match somewhat the room sounds on the omnis. Just a smidge. It worked out alright. I do not like adding reverb or alignment, but this time it was called for. And it worked.

I would say time alignment depends on the situation. Sometimes I think one must.


Cheers

[David Spearritt]

Originally Posted by Recording David

I did some sessions with Simon Eadon at the end of last year and learned a pretty cool tip for soprano (or other singer) and piano.

David, you don't know if Simon recorded Barbara Bonney's "Fairest Isle" Decca CD do you. Its one of the best soprano sounds I have ever heard.

[David Spearritt]

Here are two files, stereo main, and spot of the same section. These are as recorded. I find things come into focus when the spot is delayed about 200 samples. Many thanks to anyone who has any advice.

[fallforward]

I always do an impulse recording (usually two sticks or my hands slapped together) with all mic's open to get a time marker that I can use to align everything to the main stereo pair. Works wonders and takes very little time to align in the computer.

Great tip! That will become a SOP for me for any recording in a big hall!
Robby

[studer58]

Originally Posted by fallforward

Great tip! That will become a SOP for me for any recording in a big hall!
Robby

I recorded an orchestra last night, with singer soloist, and had an omni pair over the conducter, outriggers left and right edges and solo spot mic about halfway between main pair and left outrigger, plus a pair of woodwind spots further back in the ensemble. I was recording to multitrack so they remain as discrete mic inputs in Reaper. Remembering this discussion I made a set of clap recordings at the end of the concert, in front of each spot mic and directly below the main pair. I have a set of waveforms with the 'clap spike' displaced from one another by some intervals for each of those mics....so which "benchmark" should I line them all up to ?

Incidentally, with the vocal spot equidistant between the main pair and the left side outrigger, you'd expect some phasiness perhaps...but I don't hear it in the playback
Ray

[tenor39]

I guess I should have been more precise in my description. You don't need to do the "clap test" in front of each mic. Once you have everything setup and all mic's open, pick a spot in the center of the stage that is deep in the soundfield. If you had a stereo pair on the Winds, stand where the Brass and Percussion would be and do your test. Being centered will put you equidistant from your main pair over the conductor and allow you to align all the other mic's to that pair. The impulse sound must come from a spot deeper than your deepest mic's.

[pkautzsch]

Originally Posted by fifthcircle

I think your problem is this. While your main pair isn't spaced terribly wide, it is wide enough that the delay from the spot to each mic is not exactly the same. Therefore, when you delay it, there is still a bit of a mismatch in your time alignment.

If that theory is right, it would be worth trying to send the spot to two tracks panned hard L/R, each delayed individually. Difference will probably be just a few samples, so the image stays centerish.

When delaying the spot some milliseconds (think Haas) more than distance spot-to-main requires, the mismatch wouldn't matter, though.

[David Spearritt]

Originally Posted by pkautzsch

If that theory is right, it would be worth trying to send the spot to two tracks panned hard L/R, each delayed individually. Difference will probably be just a few samples, so the image stays centerish.

When delaying the spot some milliseconds (think Haas) more than distance spot-to-main requires, the mismatch wouldn't matter, though.

Yes I tried that and it didn't seem to fix things convincingly as it was pretty much centred. The simple spot delay of about 200 samples made all the difference. In future I will try a different technique to eliminate the need for any decay and therefore the dependence on multi-tracking.

[Ozpeter]

David, I haven't downloaded your samples yet but will.

Banging two sticks together, clapping, etc - well, a neater way is to use a dog training clicker. It's a little thing that emits a sharp click when the button is pressed. Any pet store should have them. Or use a 'party popper' with the ribbon stuff carefully removed in advance, but they tend to leave a little smoke and smell in the air, leading to your possible removal from the hall.

David - in the good old days when I used to record a lot of voice and piano demos, the way I set things up with a stereo pair only was as follows -

Have the singer centre stage. Have the piano to the left of the singer (as you face the singer) with the pianist's back to you, and with the pianist a little closer to the edge of the stage than the singer. Now bring the tail of the piano to the right somewhat - perhaps to the 45 degree point. The pianist and singer then have good eye contact, the piano can be on full stick because it's firing a bit away from the stereo pair, and then tweak to suit taste and circumstance (eg move mic closer or further, and/or move singer back or forward.

After a while pianist Malcolm Martineau* used to automatically set himself up like that during the warm up before I arrived, as he grew to like that way.

But there are, of course, many, many other possibiltities.

(*He once gave me a good piece of advice - "Arrive an hour early for everything. You'll live longer.")

[panatrope]

With the recent recording of the Berlioz 'L'Enfance du christ' we had a similar problem with the soloist spotters (main coincident pair behind the conductor plus outriggers, soloists 2m either side of conducter, definitely not obeying the 3:1 rule) which were not used at rehearsal but judged a necessity on the day. Only a brief sound check prior to performance. A live stereo mix was made for broadcast shortly thereafter, a multitrack recording made in parallel for a prospective CD. At the sound check it was clear that at optimum soloist balance the interference was greatest (ie., identical acoustic gain). Under-running or over-running the soloist mic made the effect less obvious. The choice for the broadcast was to put the soloist slightly more forward (because of the more casual radio listening environment). The subsequent CD producer used some delay in the soloists mics and this reduced the problem.

The approach that seems most logical is to make the sound from the spot arrive slightly after the sound direct to the main pair. True coincidence will make the comb filtering more apparent because it is in the more sensitive part of the ear's response, and because it will shift (like the 'shortwave' or flanging effect) as the soloist moves position even a small amount. Arrival a few milliseconds after the wavefront arrives at the main pair will lower the starting frequency of the comb effect, and will also invoke the Haas/precedence/first wavefront effect, namely that the ear will localise on the first but softer wavefront, but the loudness will still be determined by the loudness of the spot mic.

Not easy to do in a pure analog situation. Though the BBC did build a 3ms passive delay line (26-section all-pass filter) for one of its early FM limiters to avoid overshoot and audible distortion by ensuring that the gain of the limiting stage had been reduced by the appropriate amount before the peak hit it. Find a pair of those in the secondhand shop and you have an analog delay line of about 130 samples ..... Just a thought!